Photographs of the Sandy Hook school clearly show a car owned by Christopher Rodia at the school. This was supposedly the car used by Adam Lanza to get to the school supposedly carrying a bunch of firearms. A gun or guns were evidently also found in the trunk of the car, including the Bushmaster rifle which Adam could not have used in the shooting.
Why, then, was there a clumsy attempt to cover up the fact that it was Rodia's car? This is explored in the film.
More food for thought:
One witness says that police arrived at the scene before the shooting started.
Recorded police radio shows that Rodia was present when his car's plates were 'run' by police. Rodia's car was present at Sandy Hook school (see photo download below). Therefore, Rodia was present at Sandy Hook school.
Some officer is recorded speaking the words "end the life of Adam" over police radio.